I've been getting down to 20F for a few years now with a Jacks R Better 3 season quilt set. Cheaper than the peapod, easier to use with the center drawcord on the foot end.

You'll easily spend $500 on just a down sleeping bag, so two 3 season down quilts are actually cheaper than a pad and bag for the money.

I picked up a Winter Yeti from Warbonnet a couple years back - it's a 0 degree down 3/4 length quilt with a mylar liner, and I do not doubt that it's rated accurately - there's some serious loft to it and it's got a differential cut to the baffles, so no compression possible. I haven't been down to 0 with it yet but maybe this winter. It actually weighs less than the 20 oz JRB 3 season full length quilt.

Shop the options... you will be suprised.